Liner for a casting shake out and reclaimer

ABSTRACT

A tumbling unit such as a casting shake-out unit, rotary media drum, sand reclaimer or the like includes a cylindrical outer shell and a cylindrical inner liner. The inner liner is formed of a series of interfitting segments. The segments each have an inner surface, an outer surface, side edges, a front edge, a back edge, and two vanes extending from the outer surface. The side edges of the segments have a groove and the grooves of neighboring segments define a channel between the segments. A pin in the channel urges the neighboring segments apart to form a tight interfit among the segments in a row of the liner. The pin conforms in shape and size to the cross section of the vanes, and aligns with the vanes of the adjacent segments to form a continuous spiral upon the outside of the liner.

CROSS-REFERENCE TO RELATED PATENTS

The subject matter of this application is related to the subject matter of the patents of Michael S. Didion and Charles J. Didion, pertaining to Interlocking Liner for a Casting Shake Out Unit, now U.S. Pat. No. 6,273,176, and Interlocking Liner for a Casting Shake Out Unit, now U.S. Pat. No. 5,638,890, and both owned by a common assignee.

BACKGROUND OF THE INVENTION

This invention relates to casting shake-out units used to separate or remove sand from castings in a foundry, a mill, or other works, and in particular, to a liner which forms the inner surface of the shake-out unit.

In the formation of a tumbling mill, such as a casting shake-out unit, rotary separator, media drum, material drier, lump crusher reclaimer, blending drum, sand screen, or the like, it is desirable to form the inner surface of the mill from segments. Thus, when individual segments wear out, they can be replaced easily and rapidly without incurring a significant amount of downtime or expense.

An example of a shake-out unit having segmented inner liners is shown in U.S. Pat. No. 3,998,262 which is assigned to the same assignee as the present invention, and which is incorporated herein by reference. As set forth in that patent, the inner cylinder forming the inner surface of the unit is formed from a series of interconnected modular components. The operation of that unit, for its intended purpose, has performed highly satisfactorily. However, when the casting shake-out unit is operated continuously, the wear on the components causes the components or segments to gradually loosen. This requires a retightening of the entire formed inner surface. This retightening operation requires that the operator incur a significant amount of down time.

It is desirable for the mill to operate for a longer period before the segments begin to loosen and separate. In U.S. Pat. Nos. 4,502,808, 5,638,887, and 5,638,890, all of which are assigned to the same assignee as the present invention and incorporated herein by reference, the side edges of the segments are grooved to define a channel between neighboring segments. A pin or bar is inserted in the channel. In a completed lining, the bars tend to urge the segments apart, thus creating a tight fig in the completed cylindrical lining. These have also worked well in industrial applications.

A unique aspect of the present invention is a pair of spaced apart vanes upon the outer surface of a liner segment. The vanes of adjacent segments abut each other and form a spiral that advances sand along a drum towards an outlet as the drum turns.

DESCRIPTION OF THE PRIOR ART

Other patents of the inventors show various related liner segments. In U.S. Pat. No. 6,273,176, a plurality of T shaped pins engage grooves in the edges of segments. The pins lock adjacent segments to one another and prevent shifting of segments during wear. As a segment wears, the pins allow the segments to tighten their grip upon one another.

In U.S. Pat. No. 5,638,890, a liner segment has three vanes upon the outer surface and a diagonal vane upon the inner surface. The liner segment has cooperating tongues and pockets to inter connect adjacent offset liner segments. However, the three vanes have two outer vanes oriented at an angle. The angle of the outer vanes allows sand, media, or debris to accumulate where vanes of adjacent segments abut. A chokepoint full of sand, media, or debris slows rotation of the drum, wears the drum, and delays or impedes the flow of other sand, media, or debris. Further, as the outer vanes wear, the segment pivots upon the center vane. Sand, media, or debris act as an abrasive and in normal drum operations, the vanes wear. For various reasons, one outer vane likely wears different than the other outer vane. The change in depth to the outer vanes allows the segment to rotate or rock upon the edge of the center vane. A segment that rocks causes premature wear to the drum and stresses the tongue and pocket connection of adjacent segments.

The present art overcomes the limitations of the prior art. That is, the art of the present invention, a liner for a casting shakeout and reclaimer, uses two vanes upon the outer surface of a segment to move sand, media, or debris towards an outlet with minimal chokepoint creation and less downtime for an operator of a drum.

SUMMARY OF THE INVENTION

A tumbling unit such as a casting shake-out unit, rotary media drum, sand reclaimer or the like, is provided. The tumbling unit includes a cylindrical outer shell and a cylindrical inner shell. The inner liner is formed of a series of interfitting segments. The segments each have an inner surface, an outer surface, side edges, a front edge, a back edge, and rifling or vanes extending from the outer surface. The side edges of the segments have a groove formed therein which extends the length of the edges. The grooves of neighboring segments define a channel between the segments. To interfit the segments, the segments include tongues partially along their segment front and back edges and cutouts, or pockets, in their corners. The tongues and cutouts are shaped and positioned to enable the segments to interfit with each other.

A pin is received in the channel to urge the neighboring segments apart and to form a tight interfit among the segments in a row of the liner. The retaining pin has a body having side surfaces, a top surface, and a bottom surface. A vane extends along each side surface which is shaped and sized to be received in the grooves of the neighboring segments. An arm extends upwardly from the pin body top surface. When the pin is placed between two neighboring segments, it separates the segments. The pin arm conforms in shape and size to the profile or cross section of the vanes, and is positioned on the pin body to be in alignment with the vanes of the adjacent segments to form a continuous spiral rifling on the liner. The pins have cutouts at opposite ends thereof which conforming generally in size and shape to the profile of the segment cutouts.

In the preferred embodiment, the segments include an outer surface with two vanes of rifling. A first vane extends from the center of a side edge towards the back edge. A second vane, mutually parallel and spaced apart from the first vane, extends from the front edge towards the opposite side edge from the first vane. The first vane and the second vane have a depth at a constant radius slightly less than the radius of the drum and greater than the radius of the segment. Opposite the vanes, the inner surface has a plurality of slots of greater number than in prior patents assigned to this assignee.

Therefore, it is an object of the invention to provide a new and improved liner for a casting shakeout and reclaimer.

It is a further object of the present invention to prevent the accumulation of sand at the meeting of two vanes and hence a chokepoint impeding the flow of sand, media, or debris out of a drum.

It is a further object of the present invention to prevent rocking of a liner due to uneven wear of the vanes.

It is a further object of the present invention to prevent premature wear of a drum due to rocking of the segments.

It is a further object of the present invention to increase the sand handled per hour of operation of the drum by twelve per cent (12%) over existing machinery.

It is a further object of the present invention to reduce the weight of a segment by fifteen per cent (15%) over existing segments to ease operation of the drum and handling of the segments during installation, repair, and replacement.

These and other objects may become more apparent to those skilled in the art upon review of the invention as described herein, and upon undertaking a study of the description of its preferred embodiment, when viewed in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial perspective end view of a tumbling unit, such as a casting shakeout unit, which is partially exploded to show one segment of the lining removed from the unit;

FIG. 2 is a front view of a segment which forms the lining for the tumbling unit;

FIG. 3 is a top plan view, showing the outer surface and vanes of the segment that advance sand along the shakeout unit or drum;

FIG. 4 is a bottom plan view, showing the inner surface of a segment; and,

FIG. 5 is a top plan view of interconnected segments showing the vanes abutting.

The same reference numerals refer to the same parts throughout the various figures.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present art overcomes the prior art limitations by providing two vanes of constant cross section upon a segment. The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

A tumbling mill 1 is shown generally in FIG. 1. The tumbling mill 1 is preferably a mill constructed and operated in the manner disclosed in U.S. Pat. No. 3,998,262 to remove sand from casting by tumbling the castings. As shown, the mill 1 generally includes an outer cylinder or drum 3 and an inner cylinder 5. The inner cylinder 5 is of a smaller diameter than the outer cylinder 3, and the two cylinders define a space 7 between the cylinders. The inner liner or cylinder 5 is made of a plurality of interlocking segments 9 which fit together to form the cylinder 5. The segments work in cooperation with the drum to move sand along the drum to an outlet. Importantly, the segments 9 positively lock together so that segments will not fall out of the lining as they wear. This advantageously increases the time the mill may be continuously operated before it has to be shut down to tighten the inner liner 5. Preferably the segments are rectangular in shape and curved along their longitudinal axis. Alternatively, the segments may have hexagonal and triangular shapes and also curved along their longitudinal axis.

The segment 9 is similar to the segments described in U.S. Pat. No. 5,638,890. Each segment 9 includes a generally arcuate body 11 having an inner surface 13, an outer surface 15, side edges 17, and front and back edges 19. Each segment preferably covers approximately 20 degrees of arc to approximately 45 degrees of arc. To space the segments 9, and hence, the inner cylinder 5, from the outer cylinder 3, each segment 9 has diagonally extending rifling or vanes 21 upon its outer surface 15. The vanes 21 are positioned on a segment 9 so that when a plurality of the segments are connected to form the inner cylinder 5, the vanes from one segment abut respective vanes from neighboring segments to provide continuous rifling that functions as a spiral screw upon the outer surface of the segments and within the drum. Building upon the prior patents, the inner cylinder 5 is preferably more perforated so that the sand which is separated from the castings may fall into the space 7 between the inner and outer cylinders. As the drum turns, the rifling or vanes move sand, media, or debris towards an outlet of the drum. The segments 9 thus have a plurality of holes or perforations 23 formed therein to allow sand or debris to fall into the space 7 between the inner and outer cylinders. The perforations have a somewhat rectangular shape with rounded ends. A slot or groove 25 is formed along side edges 17 to receive a pin 27 which spaces the segments apart in the completed inner cylinder and tightens the fit between the segments of the inner cylinder. The pin 27 is described in U.S. Pat. No. 5,638,890. The groove 25 extends the full length of the side edges 17.

To enable the segments 9 to interfit and to interlock with each other, each segment includes a tongue 29 extending from the approximate center of the front and back edges 19 and generally rectangular cutouts 31 at the four corners of the liner body 11. The cutouts 31 define pockets 33 when two segments 9 are placed adjacent each other along their side edges 17. The formed pocket 33 receives the tongue 29 of a further segment 9 which is placed adjacent the two segments along the front and back edges 19 of the segments, as later seen in FIG. 5. The body, however, includes a raised portion 35 on the outer surface 15 which covers the cutouts 31, as seen in FIG. 4. Thus, the pockets 33 are closed on one side. When the liner 5 is assembled, the covers 35 rest on the tongues 29, thereby interlocking the segments 9 of adjacent different rows of segments.

As illustrated in FIGS. 2 and 4, the segments 9 exclude rifling on their inner surfaces 13. The sand and castings travel through the inner cylinder under the rotation and inclination of the drum.

When the segments 9 are interconnected, the pins 27 tighten the liner or inner cylinder 5, as set forth in U.S. Pat. No. 4,502,808, to lengthen the time before the segments come loose from each other due to continuous operation of the mill containing the drum. The interconnection of the segments, in turn, prevents a segment from falling out when the pin wears. Thus, if a pin 27 wears, the interaction between a tongue 29 and its associated pocket 33 will prevent the segment from falling out of the inner cylinder 5. Although the segment will be loose when the pin wears through, the segment will not fall out. This will allow the operator time to shut down the mill normally and to insert a new pin or a new segment.

As can be appreciated, the segments of the present invention will cooperate with each other to prevent a segment from separating from the lining 5 when a pin wears or breaks. Although the segment may be somewhat loose, the mill 1 will still be operable, at least for a short period of time, before the segment must be replaced. This will allow for a normal shut down of the machine, rather than an abrupt or emergency shut down of the machine which would be needed if the segment did separate from the lining. The pin will provide a smooth and continuous transition between the segments, so that the castings and sand travel upon only continuous substantially uninterrupted inner surface for the lining and continuous substantially uninterrupted vanes or spiral rifling along the liner outer surface.

From the aforementioned description, a liner for a casting shakeout and reclaimer has been described. This liner is uniquely capable of reducing chokepoints and bottlenecks of sand, media, or debirs,between a liner and a drum. This liner and its various components may be manufactured from many materials including but not limited to ferrous and non-ferrous metals, their alloys, polymers, high density polyethylene, polypropylene, nylon, and composites.

Variations or modifications to the subject matter of this invention may occur to those skilled in the art upon reviewing the development as described herein. Such variations, if within the scope of this development, are intended to be encompassed within the principles of this invention, as explained herein. The description of the preferred embodiment, in addition to the depiction within the drawings, are set forth for illustrative purposes only. 

1. A tumbling unit such as a casting shake-out unit, rotary media drum, sand reclaimer or the like, the tumbling unit comprising: a cylindrical outer shell; a cylindrical liner positioned within said outer shell, said liner being formed of a series of interfitting segments; said segments having an inner surface, an outer surface, mutually parallel side edges, a front edge, a back edge, and two parallel vanes extending from said outer surface; the side edges of the segments having a groove formed therein and extending the length of said side edges, the grooves of neighboring segments defining a channel therebetween; and an elongate retaining pin received in said channel to urge adjacent segments apart thus forming a tight interfit among the segments in a row of said liner.
 2. The tumbling unit of claim 1 wherein said liner segments include tongues on said segment front and back edges, and cutouts in corners of said segments; said tongues and cutouts being shaped and positioned to enable said segments to interfit with each other; said pins having cutouts at opposite ends thereof; said pin cutouts conforming generally to the profile of the segment cutouts.
 3. The tumbling unit of claim 1 wherein said vanes have a constant shape in cross section.
 4. The tumbling unit of claim 3 wherein said vanes have a rectangular cross section.
 5. A tumbling unit, such as a casting shake-out unit, rotary media drum, sand reclaimer or the like, having a cylindrical outer shell and a cylindrical liner positioned within the outer shell, and the liner being formed of a series of interfitting segments, wherein the improvement comprises: said segments having an inner surface, an opposite outer surface, mutually parallel side edges, a front edge, an opposite back edge, and two parallel vanes extending outward from said outer surface wherein said vanes travel within the gap between the outer shell and the liner; two grooves, each formed upon one of said side edges extending along the length of said side edge, said grooves of neighboring segments defining a channel therebetween; and elongate retaining pins received in said channels to urge adjacent segments apart thus tightly interfitting said segments in a row of said liner.
 6. The tumbling unit of claim 5 further comprising: tongues on each of said front and back edges; cutouts in the corners of said segments, wherein said tongues and said cutouts being shaped and positioned to interfit said segments adjacent to each other; and, said pins having cutouts at opposite ends thereof; said pin cutouts conforming generally to the profile of the segment cutouts.
 7. The tumbling unit of claim 5 wherein said vanes have a constant shape in cross section.
 8. The tumbling unit of claim 7 wherein said vanes have a rectangular cross section.
 9. The tumbling unit of claim 5 wherein said segments have a generally rectangular shape. 